For many years, petroleum has been recovered from subterranean reservoirs through the use of drilled wells and production equipment. During the production of desirable hydrocarbons, such as crude oil and natural gas, a number of other naturally occurring substances may also be encountered within the subterranean environment. The term “stimulation” generally refers to the treatment of geological formations to improve the recovery of liquid hydrocarbons (e.g., formation crude oil and/or formation gas). Common stimulation techniques include well fracturing and acidizing operations.
Oil and natural gas are found in, and produced from, porous and permeable subterranean formations. The porosity and permeability of the formation determine its ability to store hydrocarbons, and the facility with which the hydrocarbons can be extracted from the formation. Hydraulic fracturing is commonly used to stimulate low permeability geological formations to improve the recovery of hydrocarbons. The process can involve suspending chemical agents in a well-treatment fluid (e.g., fracturing fluid) and injecting the fluid down the wellbore. However, the assortment of chemicals pumped down the well can cause damage to the surrounding formation by entering the reservoir rock and blocking the pore throats. It is known that fluid invasion can have a detrimental effect on gas permeability and can impair well productivity. In addition, fluids may become trapped in the formation due to capillary end effects in and around the vicinity of the formation fractures.
In efforts to reduce phase trapping, additives have been incorporated into well-treatment fluids. Generally, the composition of additives comprises multi-component chemical substances and compositions that contain mutually distributed nanodomains of normally immiscible solvents, such as water and hydrocarbon-based organic solvents, stabilized by surfactants (e.g., microemulsions). The incorporation of additives into well-treatment fluids can increase crude oil or formation gas, for example by reducing capillary pressure and/or minimizing capillary end effects.
Although a number of additives are known in the art, there is a continued need for more effective additives for increasing crude oil or formation gas for wellbore remediation, drilling operations, and formation stimulation.